Benefit Plans

Our employees ceased to participate in the Pfizer, Inc. U.S. qualified defined benefit plans and the U.S. retiree medical plan effective December 31, 2012, and liabilities associated with our employees under these plans were retained by Pfizer. Pfizer is continuing to credit certain employees' service with Zoetis generally through December 31, 2017 (or termination of employment from Zoetis, if earlier) for certain early retirement benefits with respect to Pfizer's U.S. defined benefit pension and retiree medical plans. Pension and postretirement benefit expense associated with the extended service for certain employees in the U.S. plans totaled approximately $2 million in each three month period ended April 2, 2017, and April 3, 2016.

The following table provides the net periodic benefit cost associated with our international defined benefit pension plans:



	Three Months Ended
	April 2,			April 3,
(MILLIONS OF DOLLARS)	2017			2016
Service cost	$	2		$	2
Interest cost	1			1
Expected return on plan assets	(1		)	(1		)
Curtailment and settlement (gain)/loss	1			—
Net periodic benefit cost	$	3		$	2

Total company contributions to the international pension plans were $3 million for each of the three months ended April 2, 2017, and April 3, 2016. We expect to contribute a total of approximately $7 million to these plans in 2017.